Electrical equipment is commonly installed in enclosures, both to protect the equipment from accidental/intentional damage, inhibit interference by unqualified and/or unauthorized personnel, and to protect nearby persons from live electrical components of the equipment.
One form of electrical equipment enclosure comprises a back pan that, in use, is fixed to a wall or other support surface, and a main section that is hinged to the back pan and within which electrical equipment is mounted. The front and rear of the main section are typically open. A door may also be provided, hinged to the front of the main section. Parts of the electrical equipment to which access is required in operation of the equipment may be exposed at the front of the main section. The door may include a lock that is actuated by a key. Parts of the electrical equipment to which more restricted access is limited may be exposed only at the back of the main section. For example, controls may be at the front, and wiring may be at the back. Thus, in this configuration, removal of the equipment may be possible only by accessing the back of the main section.
Access to the rear of the main section of existing electrical cabinets is conventionally prevented through the use of screw rods or by a key-operated lock which secure the main section to the back pan. For example, one cabinet enclosure sold by Raxxess, includes a threaded rod that the extends from the front of the main section through to the back pan where it is threaded into a mating hole in the back pan. The opposite end of the rod is accessible from the front of the main section. The rod is removed by unscrewing the rod. Such locking rods are relatively easy to disable and, thus, provide only minimum security. Also, if the rod requires an uncommon driver bit for removal, the authorized person must remember to carry the special driver bit whenever access to the cabinet might be necessary.
Another common cabinet enclosure on the market uses a key-operated lock system. One lock is located on the side of the cabinet between the main section and the back pan, and locks the two together. A second lock may be included on the front door which locks the door to the main section. One such cabinet is sold by the Lowell Manufacturing Company, as the L250 cabinet. These key-operated locks have been found to be inconvenient since several inches (i.e., about 10–20 cm) of clearance must be provided alongside the cabinet on the side where the lock is mounted (typically the side opposite from the hinges) to allow a user to reach the lock and insert and turn the key.
A need, therefore, exists for an improved locking mechanism for use with such electrical enclosures which permits unlocking of the main section of the enclosure from the back pan which significant clearance required on the side of the cabinet.